Subscribe: Neuropsychology - Vol 24, Iss 1
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Neuropsychology - Vol 30, Iss 8

Neuropsychology focuses on (a) basic research, (b) the integration of basic and applied research, and (c) improved practice in the field of neuropsychology. The primary function of Neuropsychology is to publish original, empirical research on the relation

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Copyright: Copyright 2016 American Psychological Association

A critical evaluation of the validity of episodic future thinking: A clinical neuropsychology perspective.


Objective: Episodic future thinking is defined as the ability to mentally simulate a future event. Although episodic future thinking has been studied extensively in neuroscience, this construct has not been explored in depth from the perspective of clinical neuropsychology. The aim of this critical narrative review is to assess the validity and clinical implications of episodic future thinking. Method: A systematic review of episodic future thinking literature was conducted. PubMed and PsycInfo were searched through July 2015 for review and empirical articles with the following search terms: “episodic future thinking,” “future mental simulation,” “imagining the future,” “imagining new experiences,” “future mental time travel,” “future autobiographical experience,” and “prospection.” Results: The review discusses evidence that episodic future thinking is important for adaptive functioning, which has implications for neurological populations. To determine the validity of episodic future thinking, the construct is evaluated with respect to related constructs, such as imagination, episodic memory, autobiographical memory, prospective memory, narrative construction, and working memory. Although it has been minimally investigated, there is evidence of convergent and discriminant validity for episodic future thinking. Research has not addressed the incremental validity of episodic future thinking. Practical considerations of episodic future thinking tasks and related constructs in a clinical neuropsychological setting are considered. Conclusions: The utility of episodic future thinking is currently unknown due to the lack of research investigating the validity of episodic future thinking. Future work is discussed, which could determine whether episodic future thinking is an important missing piece in standard clinical neuropsychological assessment. (PsycINFO Database Record (c) 2016 APA, all rights reserved)(image)

Neuronal correlates of serial position performance in amnestic mild cognitive impairment.


Objectives: Delayed recall of the first words of a list—the primacy position—is thought to be particularly dependent on intact memory consolidation. Hippocampal volume has been suggested as the primary neuronal correlate of delayed primacy recall in cognitively normal elderly individuals. Here, we studied the association of hippocampal volume with primacy recall in individuals with amnestic mild cognitive impairment (aMCI). Method: We investigated serial position performance in 88 subjects with aMCI using a 16-word list (the California Verbal Learning Test [CVLT]). Primacy and recency performance were measured during learning and delayed recall. Hippocampal volumes were automatically determined from structural MRI scans. We conducted regression analyses with bilateral hippocampal volumes as predictors and serial position indices as outcomes. Results: After controlling for age, gender, and total intracranial volume, bilateral hippocampal volume was not associated with primacy recall either during learning or delayed recall. Primacy performance during learning was associated with the right inferior and middle temporal gyrus as well as the right inferior parietal cortex and supramerginal gyrus. During delayed recall, primacy performance was related to the bilateral supramarginal gyri. Conclusions: Our findings suggest a reduced primacy effect in aMCI already during learning, contrasting previous findings in normal cognitive aging. This might indicate impaired encoding and consolidation processes at an early stage of episodic memory acquisition. Furthermore, our data indicate that hippocampal volume may not be a relevant determinant of residual primacy performance in the stage of aMCI, which may rather depend on temporal and parietal neocortical networks. (PsycINFO Database Record (c) 2016 APA, all rights reserved)(image)

Amnesic patients show superior generalization in category learning.


Objective: Generalization is the application of existing knowledge to novel situations. Questions remain about the precise role of the hippocampus in this facet of learning, but a connectionist model by Gluck and Myers (1993) predicts that generalization should be enhanced following hippocampal damage. Method: In a two-category learning task, a group of amnesic patients (n = 9) learned the training items to a similar level of accuracy as matched controls (n = 9). Both groups then classified new items at various levels of distortion. Results: The amnesic group showed significantly more accurate generalization to high-distortion novel items, a difference also present compared to a larger group of unmatched controls (n = 33). Conclusions: The model prediction of a broadening of generalization gradients in amnesia, at least for items near category boundaries, was supported by the results. Our study shows for the first time that amnesia can sometimes improve generalization. (PsycINFO Database Record (c) 2016 APA, all rights reserved)(image)

My memories are important to me: Changes in autobiographical memory in amyotrophic lateral sclerosis.


Objective: The loss of autobiographical memories (ABM) is a pervasive feature of neurodegenerative diseases. Studies to date have not investigated ABM retrieval in amyotrophic lateral sclerosis (ALS), a multisystem disorder that may be associated with cognitive dysfunction and dementia. Method: The integrity of autobiographical memory was evaluated in 22 ALS patients compared with 28 age-matched controls using the Autobiographical Interview (AI), a semistructured interview assessing autobiographical events from discrete time periods across the life span. Results: ABM retrieval was preserved in ALS and remained rich in detail for personal events in recent (last 12-months) and remote (teenage years) time epochs. ABM retrieval was positively correlated with months since ALS symptom onset, with a greater number of contextual details being recalled as ALS progressed. A shift in how ABMs were perceived in ALS patients became apparent, with more recurrent reflection of recent life, which was also weighted with greater personal importance. Conclusion: The preservation of ABM in ALS has clinical implications for the use of life review as a therapeutic tool in a multidisciplinary care setting. (PsycINFO Database Record (c) 2016 APA, all rights reserved)(image)

Slow wave and REM sleep deprivation effects on explicit and implicit memory during sleep.


Objective: It has been debated whether different stages in the human sleep cycle preferentially mediate the consolidation of explicit and implicit memories, or whether all of the stages in succession are necessary for optimal consolidation. Here we investigated whether the selective deprivation of slow wave sleep (SWS) or rapid eye movement (REM) sleep over an entire night would have a specific effect on consolidation in explicit and implicit memory tasks. Method: Participants completed a set of explicit and implicit memory tasks at night, prior to sleep. They had 1 control night of undisturbed sleep and 2 experimental nights, during which either SWS or REM sleep was selectively deprived across the entire night (sleep conditions counterbalanced across participants). Polysomnography recordings quantified precisely the amount of SWS and REM sleep that occurred during each of the sleep conditions, and spindle counts were recorded. In the morning, participants completed the experimental tasks in the same sequence as the night before. Results: SWS deprivation disrupted the consolidation of explicit memories for visuospatial information (ηp2 = .23), and both SWS (ηp2 = .53) and REM sleep (ηp2 = .52) deprivation adversely affected explicit verbal recall. Neither SWS nor REM sleep deprivation affected aspects of short-term or working memory, and did not affect measures of verbal implicit memory. Spindle counts did not correlate significantly with memory performance. Conclusions: These findings demonstrate the importance of measuring the sleep cycles throughout the entire night, and the contribution of both SWS and REM sleep to memory consolidation. (PsycINFO Database Record (c) 2016 APA, all rights reserved)(image)

The effectiveness and unique contribution of neuropsychological tests and the δ latent phenotype in the differential diagnosis of dementia in the uniform data set.


[Correction Notice: An Erratum for this article was reported online in Neuropsychology on Nov 17 2016 (see record 2016-55595-001). The first sentence in the note to Table 6 should read “Odds ratios (OR) greater than 1 mean that better scores on a test are associated with greater odds of the first diagnosis shown in the Comparison column, whereas OR less than 1 mean that better scores on a test are associated with lower odds of the first diagnosis shown in that column.” Also, the first sentence in the note to Table 7 should read “Odds ratios (OR) greater than 1 mean that higher scores (less severe dementia) are associated with greater odds of the first diagnosis shown in the Comparison column, whereas OR less than 1 mean that higher scores (less severe dementia) are associated with lower odds of the first diagnosis shown in that column.”] Objective: Two main approaches to the interpretation of cognitive test performance have been utilized for the characterization of disease: evaluating shared variance across tests, as with measures of severity, and evaluating the unique variance across tests, as with pattern and error analysis. Both methods provide necessary information, but the unique contributions of each are rarely considered. This study compares the 2 approaches on their ability to differentially diagnose with accuracy, while controlling for the influence of other relevant demographic and risk variables. Method: Archival data requested from the NACC provided clinical diagnostic groups that were paired to 1 another through a genetic matching procedure. For each diagnostic pairing, 2 separate logistic regression models predicting clinical diagnosis were performed and compared on their predictive ability. The shared variance approach was represented through the latent phenotype δ, which served as the lone predictor in 1 set of models. The unique variance approach was represented through raw score values for the 12 neuropsychological test variables comprising δ, which served as the set of predictors in the second group of models. Results: Examining the unique patterns of neuropsychological test performance across a battery of tests was the superior method of differentiating between competing diagnoses, and it accounted for 16–30% of the variance in diagnostic decision making. Conclusion: Implications for clinical practice are discussed, including test selection and interpretation. (PsycINFO Database Record (c) 2016 APA, all rights reserved)(image)

Cognitive deficits after aneurysmal and angiographically negative subarachnoid hemorrhage: Memory, attention, executive functioning, and emotion recognition.


Objective: The authors’ aim was to investigate cognitive outcome in patients with aneurysmal and angiographically negative subarachnoid hemorrhage (aSAH and anSAH), by comparing them to healthy controls and to each other. Besides investigating cognitive functions as memory and attention, they focused on higher-order prefrontal functions, namely executive functioning (EF) and emotion recognition. Method: Patients and healthy controls were assessed with tests measuring memory (15 Words Test, Digit Span), attention and processing speed (Trail Making Test A and B), EF (Zoo Map, Letter Fluency, Dysexecutive Questionnaire), and emotion recognition (Facial Expressions of Emotion Stimuli and Tests). Between-groups comparisons of test performances were made. Results: Patients with aSAH scored significantly lower than healthy controls on measures of memory, processing speed, and attention, but anSAH patients did not. In the higher-order prefrontal functions (EF and emotion recognition), aSAH patients were clearly impaired when compared to healthy controls. However, anSAH patients did not perform significantly better than aSAH patients on the majority of the tests. Conclusions: In the subacute phase after SAH, cognitive functions, including the higher-order prefrontal functions EF and emotion recognition, were clearly impaired in aSAH patients. Patients with anSAH did not perform better than aSAH patients, which indicates that these functions may also be affected to some extent in anSAH patients. Considering the importance of these higher-order prefrontal functions for daily life functioning, and following the results of the present study, tests that measure emotion recognition and EF should be part of the standard neuropsychological assessment after SAH. (PsycINFO Database Record (c) 2016 APA, all rights reserved)(image)

The neural mechanism of hedonic processing and judgment of pleasant odors: An activation likelihood estimation meta-analysis.


Objective: Pleasure is essential to normal healthy life. Olfaction, as 1 of the neurobehavioral probes of hedonic capacity, has a unique advantage compared to other sensory modalities. However, it is unclear how olfactory hedonic information is processed in the brain. This study aimed to investigate olfactory hedonic processing in the human brain. Method: We conducted an activation likelihood estimation (ALE) meta-analysis on 16 functional imaging studies that examined brain activation in olfactory hedonic processing-related tasks in healthy adults. Results: The results show that there is a core olfactory hedonic processing network, which consists of the bilateral parahippocampal gyrus/amygdala (BA34), the left middle frontal gyrus (BA6), the right middle frontal gyrus/lateral orbitofrontal cortex (OFC; BA10), the bilateral cingulate gyrus (BA32), the right lentiform nucleus/lateral globus pallidus, the right medial frontal gyrus/medial OFC (BA11), the left superior frontal gyrus (BA10), and the right insula (BA13). Moreover, our findings highlight that the right hemisphere is predominant in explicit odor hedonic judgment. Finally, the results indicate that there are significant differences in brain activation for hedonic judgment and passive smelling. Conclusion: These results support the hypothesis that the OFC plays a key role in explicit hedonic judgment. (PsycINFO Database Record (c) 2016 APA, all rights reserved)(image)

Nonlinear associations between plasma cholesterol levels and neuropsychological function.


Objective: Although both high and low levels of total and low-density lipoprotein (LDL) cholesterol have been associated with poor neuropsychological function, little research has examined nonlinear effects. We examined quadratic relations of cholesterol to performance on a comprehensive neuropsychological battery. Method: Participants were 190 older adults (53% men, ages 54–83) free of major medical, neurologic, and psychiatric disease. Measures of fasting plasma total and high-density lipoprotein (HDL) cholesterol were assayed, and LDL cholesterol was calculated. Participants completed neuropsychological measures of attention, executive function, memory, visuospatial judgment, and manual speed and dexterity. Multiple regression analyses examined cholesterol levels as quadratic predictors of each measure of cognitive performance, with age (dichotomized as b = −.0013, p = .039), such that the 70+ group performed best at high and low levels of total cholesterol than at midrange total cholesterol (U-shaped) and the b = −.0020, p = .026) and log of the Trail Making Test, Part B (b = .0001, p = .044). Quadratic associations between HDL cholesterol and cognitive performance were nonsignificant. Conclusions: Results indicate differential associations between cholesterol and neuropsychological function across different ages and domains of function. High and low total and LDL cholesterol may confer both risk and benefit for suboptimal cognitive function at different ages. (PsycINFO Database Record (c) 2016 APA, all rights reserved)(image)

Effects of bilingualism on vocabulary, executive functions, age of dementia onset, and regional brain structure.


Objective: To review the current literature on the effects of bilingualism on vocabulary, executive functions, age of dementia onset, and regional brain structure. Method: PubMed and PsycINFO databases were searched (from January 1999 to present) for relevant original research and review articles on bilingualism (but not multilingualism) paired with each target neuropsychological variable published in English. A qualitative review of these articles was conducted. Results: It has long been known that mean scores of bilinguals fall below those of monolinguals on vocabulary and other language, but not visual-perceptual, format cognitive tests. Contemporary studies that have reported higher mean scores for bilinguals than monolinguals on executive function task-switching or inhibition tasks have not always been replicated, leading to concerns of publication bias, statistical flaws, and failures to match groups on potentially confounding variables. Studies suggesting the onset of Alzheimer’s disease occurred about 4 years later for bilinguals versus monolinguals have not been confirmed in longitudinal, cohort, community-based, incidence studies that have used neuropsychological testing and diagnostic criteria to establish an age of dementia diagnosis. Neuroimaging studies of regional gray and white matter volume in bilinguals versus monolinguals show inconsistencies in terms of both the regions of difference and the nature of the difference. Conclusions: Resolving inconsistencies in the behavioral data is necessary before searching in the brain for neuroanatomical correlation. Comparisons of balanced versus language-dominant groups within the same ethnoculture combined with objective measurement of bilingualism could better match groups on potentially confounding variables. (PsycINFO Database Record (c) 2016 APA, all rights reserved)(image)

Engagement with the auditory processing system during targeted auditory cognitive training mediates changes in cognitive outcomes in individuals with schizophrenia.


Background: Individuals with schizophrenia who engage in targeted cognitive training (TCT) of the auditory system show generalized cognitive improvements. The high degree of variability in cognitive gains maybe due to individual differences in the level of engagement of the underlying neural system target. Method: 131 individuals with schizophrenia underwent 40 hours of TCT. We identified target engagement of auditory system processing efficiency by modeling subject-specific trajectories of auditory processing speed (APS) over time. Lowess analysis, mixed models repeated measures analysis, and latent growth curve modeling were used to examine whether APS trajectories were moderated by age and illness duration, and mediated improvements in cognitive outcome measures. Results: We observed significant improvements in APS from baseline to 20 hours of training (initial change), followed by a flat APS trajectory (plateau) at subsequent time-points. Participants showed interindividual variability in the steepness of the initial APS change and in the APS plateau achieved and sustained between 20 and 40 hours. We found that participants who achieved the fastest APS plateau, showed the greatest transfer effects to untrained cognitive domains. Conclusions: There is a significant association between an individual’s ability to generate and sustain auditory processing efficiency and their degree of cognitive improvement after TCT, independent of baseline neurocognition. APS plateau may therefore represent a behavioral measure of target engagement mediating treatment response. Future studies should examine the optimal plateau of auditory processing efficiency required to induce significant cognitive improvements, in the context of interindividual differences in neural plasticity and sensory system efficiency that characterize schizophrenia. (PsycINFO Database Record (c) 2016 APA, all rights reserved)(image)